php adding float number gives wrong result

Question

I am getting wrong result while adding float numbers, pls tell me how you programmer are escaping from this

Code:

 $tot = 0;
    $ans = (float)101;
    for($i=1; $i<= 10; $i++){
        $tot = $tot + 10.1;
    }
    var_dump($tot);
    var_dump($ans);
    if($tot == $ans){
        echo '<br />Both are equal ';
    }
    else{
        echo '<br />Both are not equal ';
    }

Result:

float 101

Both are not equal

Niranjan N Raju · Accepted Answer · 2015-10-29T07:32:49.023

1

This problem is inherited from C language.

There will be a small difference while comparing floating values,

See this, ans this

try this,

if (abs(($tot-$ans)/$tot) < 0.00001) {
    echo '<br />Both are equal ';
}
else{
    echo '<br />Both are not equal ';
}

edited Oct 29 '15 at 07:32

answered Oct 29 '15 at 07:26

Niranjan N Raju

12,047
4
22
41

number_format($tot, 5) is also a solution at least for this case – shanavas Oct 29 '15 at 07:30
But shud should understand that floating values should not be compared like this. – Niranjan N Raju Oct 29 '15 at 07:31
you mean, compare like number_format($tot, 5) ? – shanavas Oct 29 '15 at 07:33
No, this is correct, while comparing the floating values, the difference will be very minimal, so ur correct. – Niranjan N Raju Oct 29 '15 at 07:34

score 0 · Answer 2 · answered Oct 29 '15 at 07:14

0

Try with '===' , '==' compares the variable references and '===' compares the value

if($tot === $ans){
    echo '<br />Both are equal ';
}
else{
    echo '<br />Both are not equal ';
}

answered Oct 29 '15 at 07:14

AndresJ

51
5

No change if I am changing the operator – shanavas Oct 29 '15 at 07:18

php adding float number gives wrong result

2 Answers2